A cinnamate is a compound closely linked to cinnamon oil and related compounds, frequently utilized as flavorings and fragrances in various toiletries and cosmetics. Thanks to their significant UVB absorption capabilities, cinnamates find use in sunscreen products and color cosmetics that offer sun protection benefits.

The skincare industry predominantly employs Octyl methoxycinnamate as its chief UVB-blocking agent. However, its effectiveness diminishes when exposed to sunlight as it transforms into a form that absorbs UV light less efficiently. This degradation can be mitigated to some extent by incorporating certain photostabilizers like bemotrizinol, enhancing the water resistance and stability of the product.

Octocrylene, a newer cinnamate variant, exhibits both UVB and some UVA absorption properties. It is recognized for its photostability and is generally considered non-allergenic and non-irritating. Nonetheless, its widespread application in sunscreens and cosmetic items has contributed to an uptick in octocrylene sensitization, positioning it as a leading photoallergen in chemical-absorbing sunscreens.

Cinnamate allergy manifests through its chemical similarity to balsam of Peru, tolu balsam, coca leaves, cinnamic aldehyde, and cinnamic oil, making individuals allergic to these substances potentially sensitive to cinnamates. The allergic reaction may take the form of classic allergic contact dermatitis or photocontact dermatitis, with symptoms emerging immediately or after a delay.

Concerns also surround the ease with which octyl methoxycinnamate penetrates the skin, possibly fostering the production of harmful free radicals. The long-term implications of cinnamate use in skincare remain uncertain, prompting calls for further investigation.

Diagnosing a cinnamate allergy involves conducting patch tests with 1% cinnamate in petrolatum. If a cinnamate allergy is confirmed, it is advisable to avoid products containing cinnamates. Treatment for cinnamate dermatitis might involve the use of topical corticosteroids and emollients, similar to the management of acute dermatitis or eczema.

To prevent cinnamate allergy, one should meticulously read product labels and steer clear of items containing cinnamates or their derivatives. Those allergic to balsam of Peru and similar compounds should particularly avoid sunscreens with cinnamates. Seeking advice from a pharmacist for suitable alternatives is recommended.

Alternative names for cinnamate include 2-ethoxyethyl p-methoxy cinnamate, Cinoxate, Isobutyl salicyl cinnamate, Octyl methoxycinnamate, Octinoxate, and Octocrylene. The formula for 2-ethoxyethyl p-methoxy cinnamate is C14H18O4, with a CAS number of 104-28-9. Cross-reactions may occur with balsam of Peru, Tolu balsam, Coca leaves, Cinnamic aldehyde, Cinnamic oil, and Esters of cinnamates.